When you lie to someone there is a process that takes place within you, both mentally and physically. There are 3 responsive phases after deception has taken place. They are the Emotional Response, the Sympathetic Nervous Response and the Cognitive Response.
Phase 1 – The Emotional Response
When a lie is told, the deceiver recognises what they have done and they react emotionally (guilt, fear, stress, excitement). Depending on the severity of the lie, this response can vary from minor to extreme. If the deception is significant or the consequences of being detected are major, then the emotional charge attached to the lie will be increased. This is where being able to read micro expressions comes in very handy.
Phase 2 – The Sympathetic Nervous Response
This phase is the physical reaction to the emotional charge associated to the deception. The person’s nervous system will react in line with the “Fight or Flight” instinct. The body releases adrenaline which may manifest in body language signs or deception clues that can be detected. Some obvious examples include finger tapping, fidgeting, talking too quickly and rapid eye movement.
Phase 3 – Cognitive Response
This phase happens when the deceiver recognises their sympathetic nervous response. It is the conscious phase where they try to counter or disguise their deception clues they are exhibiting. For example, if a person lying to you recognises they are tapping their fingers, they may hide their hands by putting them in their pockets. Some signs are easy for the liar to recognise and then try to control, like fidgeting. Other signs, like pupil dilation, breathing and pulse rate are harder to monitor and recognise by the liar, and so, are harder to control. Don’t discount easy signs to recognise, but definitely focus on the harder ones.
As humans, we have a limit to what our brain can do. If you ask the deceiver a question, they have to use some of the power they are using to control the deception clues, to answer your question. This is where some of the “easier to recognise” body language signs will come through. Because of the limited brain power, the liar will either focus on answering the question and allow signs of deception to leak through, or focus on controlling their body language, making the verbal lie unconvincing or illogical. So, ask questions, lots of them. And quickly so they don’t have a lot of time to fabricate an answer.